1. Field of the Invention
The present invention relates to an electronic device, and in particular relates to an electronic device that transmits and receives information to and from an opposing device by means of laser light modulated according to the transmission information.
2. Description of the Related Art
Recently technologies have been proposed for realizing wireless communication at extremely high transmission speeds (for example 1 Gb/s) using laser light in the infrared wavelength region (KDDI R&D Laboratories, “The Realization of Infrared Wireless Communications at a Transmission Speed of 1 Gbit/s Using a Mobile Telephone” Internet: <URL:http://www.kddilabs.jp/press/img/83—1.pdf>, (viewed Jan. 21, 2008)). The expectation is that when transmitting data between given electronic devices by application of this technology it should be possible to complete the transmission of a large amount of data within a short period of time, even if one or more of the electronic devices is transportable and a large amount of data is to be transmitted, enabling a large reduction in communication time of wireless communication between existing electronic devices. Consequently, transmission by wireless communication of large amounts of data between devices, which would have been inconceivable using known wireless communications, is expected to be realizable, along with various other applications.
For example, in Published Japanese Patent No. 349683 a cassette for radiation detection (also called an electronic cassette) is described configured with an inbuilt radiation detection device and image memory. Radiographic images detected by the radiation detection device are stored as image data in the image memory, and image data read out from the image memory is converted into a wireless signal and output to an external signal processing circuit. In the medical field many devices are preferably not placed in an environment in which electromagnetic waves are radiating. Up to now, preferable wireless communications for the above cassette have been limited, such as to infrared communication based on IrDA (Infrared Data Association) standards, and the like. However, in such types of medical equipment, while the communication speed of infrared communication based on IrDA standards is about 115 kb/s to 6 Mb/s, a low compression ratio is selected when image data is reversibly compressed, in order to avoid any adverse effect on the interpretation of radiograms. This results in image data transfer taking an extremely long period of time. In contrast, if the above described communication by laser light could be applied for wireless communication in the above cassette, a great reduction in the duration of image data transfer could be realized.
In Japanese Patent Application Laid-Open (JP-A) No. 2007-81134 related to the above, an optical communication module is configured with a laser diode provided to a lead frame, and configured with a transparent resin section, as an adjusting means for spreading out the light output distribution of the laser diode and adjusting the output thereof. The transparent resin section is configured with a transparent resin, for encapsulating the laser diode, and containing glass filler exhibiting an ability to transmit and disperse light. The glass filler is added to the transparent resin and substantially uniformly distributed within the whole of the transparent resin.
In a mode in which wireless communication is carried out using laser light between electronic devices, if one or more of the electronic devices is transportable then the wireless communication is carried out in a state in which the two electronic devices are disposed in a positional relationship enabling wireless communication. However, since one or more of the electronic devices is transportable, if the casing of the electronic device is imparted with a pressing force, vibration or the like during communication with the laser light, the relative position of the two electronic devices changes, and there is a possibility of this leading to laser light leakage from the space interposed between the two electronic devices.
In order to address this issue, the technology of JP-A No. 2007-81134 is a technology that realizes a spreading out of the light output distribution of the optical communication module and a reduction in the light output amount of the optical communication module by repeatedly diffracting light from the laser diode using the glass filler. There is no consideration given in this technology to laser light leakage when the relative position of the electronic devices has changed during communication by laser light.